1. Field of the Invention
The present invention relates to an evaluation and qualification method for chemical solution used for a semiconductor manufacturing process, and a method for manufacturing a semiconductor device.
2. Description of the Related Art
Quality assurance of liquid is carried out by controlling the size and number of particles in the liquid. The size and number are measured by a particle counter for counting particles in liquid (Jpn. Pat. Appln. KOKAI Publication No. 9-273987). The particle counter measures the number of particles having size within a predetermined range. As it is extremely difficult to measure fine particles in liquid, the number of particles of all size existing in the liquid is not necessarily measured.
Table 1 is one example of a table showing quality assurance of liquids. This is prepared by a resist maker, and shows the quality assurance of resist solutions.
TABLE 1Per-Measured numbermissibleLotLotLotnumbernumber 1number 2number 3Size0.2-0.3μm1049200.3μm2113Solution acceptance/AcceptableAcceptableRejectablerejection determination
In Table 1, the measured values of the number of particles with respect to three types of resist lots are shown. Usually, in the quality assurance of liquids, as shown in Table 1, the number of particles which is permitted (permissible number) is provided with respect to the ranges of a plurality of particle sizes (two ranges of a range which is greater than or equal to 0.2 μm and less than 0.3 μm, and a range which is greater than or equal to 0.3 μm in Table 1). In Table 1, the example is shown in which particles greater than or equal to 0.2 μm and less than 0.3 μm are permitted up to ten, and particles greater than or equal to 0.3 μm are permitted up to two.
The resist maker selects lot numbers which can be shipped on the basis of Table 1. In Table 1, with respect to a lot number 1 and a lot number 2, the number of the particles which have been measured are within the permissible number of particles with respect to the both of the two ranges of particle sizes. However, the number of the particles in a lot number 3 exceeds the permissible number of particles. Accordingly, solution acceptance/rejection determinations result in acceptance for lot number 1 and lot number 2, and in rejection for lot number 3, and the resist solutions of lot number 1 and lot number 2 are shipped.
Users will purchase resist solutions which have been determined to be acceptable as described above from the resist maker. However, the use of a solution determined to be acceptable does not necessarily result in a great reduction of defects on a resist pattern, for example, a short circuit system defect, an opening system defect, or the like. The same thing can be said with respect to other chemical solution such as a solution including low dielectric constant material, a solution including ferroelectric material, and the like as well.